The phenomenon of cytoplasmic male sterility (CMS), consisting in the inability to produce functional pollen due to mutations in mitochondrial genome, has been described in more than 150 plant species. With the discovery of nuclear fertility restorer (Rf) genes capable of suppressing the CMS phenotype, it became possible to use the CMS-Rf genetic systems as the basis for practical utilization of heterosis effect in various crops. Seed production of sunflower hybrids all over the world is based on the extensive use of the PET1 CMS combined with the Rf1 gene. At the same time, data on Rf1 localization, sequence, and molecular basis for the CMS PET1 type restoration of fertility remain unknown. Searching for candidate genes of the Rf1 gene has great fundamental and practical value. Therefore, in this study, association mapping of fertility restorer gene for CMS PET1 in sunflower was performed. The genome-wide association study (GWAS) results made it possible to isolate a segment 7.72 Mb in length on chromosome 13, in which 21 candidates for Rf1 fertility restorer gene were identified, including 20 pentatricopeptide repeat (PPR)family genes and one Probable aldehyde dehydrogenase gene. The results will serve as a basis for further study of the genetic nature and molecular mechanisms of pollen fertility restoration in sunflower, as well as for further intensification of sunflower breeding.
GSK3 (glycogen synthase kinase 3) is a conserved protein kinase governing numerous regulatory pathways. In Drosophila melanogaster, GSK3 is encoded by shaggy (sgg), which forms 17 annotated transcripts corresponding to 10 protein isoforms. Our goal was to demonstrate how differential sgg transcription affects lifespan, which GSK3 isoforms are important for the nervous system, and which changes in the nervous system accompany accelerated aging. Overexpression of three sgg transcripts affected the lifespan in a stage- and tissue-specific way: sgg-RA and sgg-RO affected the lifespan only when overexpressed in muscles and in embryos, respectively; the essential sgg-RB transcript affected lifespan when overexpressed in all tissues tested. In the nervous system, only sgg-RB overexpression affected lifespan, causing accelerated aging in a neuron-specific way, with the strongest effects in dopaminergic neurons and the weakest effects in GABAergic neurons. Pan-neuronal sgg-RB overexpression violated the properties of the nervous system, including the integrity of neuron bodies; the number, distribution, and structure of mitochondria; cytoskeletal characteristics; and synaptic activity. Such changes observed in young individuals indicated premature aging of their nervous system, which paralleled a decline in survival. Our findings demonstrated the key role of GSK3 in ensuring the link between the pathology of neurons and lifespan.
Oleic acid is a monounsaturated fatty acid increasing oil oxidative stability. High content of oleic acid is thus a valuable trait in oilseed crops. Sunflower (Helianthus annuus L.) normally accumulates linoleic acid as a major fatty acid, but a mutant expressing a high oleic phenotype form was previously obtained by chemical mutagenesis and mapped on the sunflower genome. Several studies suggest the presence of additional genes involved in the control of the high content of oleic acid, with their expression possibly depending on the genetic background. To test this hypothesis, we performed a QTL mapping of the high oleic acid trait within two independent F2 crosses involving lines with contrasting oleic acid content from the Pustovoit All-Russia Research Institute of Oil Crops (VNIIMK) collection. We applied genotyping-by-sequencing (GBS) to construct single nucleotide polymorphism-based genetic maps and performed QTL mapping using quantitative and qualitative encoding for oleic acid content. Our results support the finding that the oleic acid content in the assessed crosses is controlled by one major effect locus. However, different dominant/recessive effects of the major locus were reported for both crosses. Additionally, a possible translocation between chromosome 7 and 14 was reported in one assessed cross. We defined a set of single nucleotide polymorphism markers for each cross which could be used for marker-assisted selection.
Publicly supported collections of cultivated germplasm are one of the key sources of new genes for crop improvement. VNIIMK is the leading organization in oil and essential oil crop breeding and seed growing in the Russian Federation with more than a century-long history. Sunflower varieties created by V.S. Pustovoit at VNIIMK became the basis for the development of the modern sunflower varieties worldwide. In the present study, 186 sunflower lines from the VNIIMK collection were characterized based on their genotype and general morphological and phenological economically-important traits. Additionally, for 99 sunflower lines fatty acid content, seed oil content, seed husk content, 100-seed weight, and seed number in the head were determined. Sequencing of RAD-libraries and the subsequent analysis have identified 65,553 variants including SNPs and indels. LD analysis revealed substantial variability across the genome. The longest LD blocks (>5,000 Kb) were found in the linkage groups 1, 5, and 17. The analysis revealed significant genetic and phenotypic diversity of the VNIIMK sunflower collection. Novel significant associations with linolenic acid content in the seeds were found on LGs 8, 9, and 17.
Starch gel electrophoresis is performed to study polymorphism of hordeins encoded by the Hrd A and Hrd B loci in 93 local accessions of cultivated barley and 37 accessions of wild barley from Turkey. Fortyfive and 32 alleles for the Hrd A locus are identified in H. vulgare and H. spontaneum, respectively, and 51 and 49 alleles are identified for the Hrd B locus. For H. vulgare, the allele frequencies range from 0.0011 to 0.2934 for the Hrd A locus and from 0.0011 to 0.0807 for the Hrd B locus. For H. spontaneum, the allele frequencies for these loci vary from 0.0089 to 0.2434 and from 0.0068 to 0.0766, respectively. Three alleles of the Hrd A and two of the Hrd В locus are common for Turkish H. vulgare and H. spontaneum. It was demonstrated that the earliest remains of barley grains were found in archaeological sites in the Middle East in Ohalo II near the Sea of Galilee dated back to the 17th millennium BC. The age of cultivated and wild barley remains from Egyptian archeological sites was determined to be 18000 years. We conclude that the southeast region of Turkey cannot be considered as the domestication center of barley. Herein, H. spontaneum from Southeastern Turkey could have been the donor of some hordein-coding alleles for H. vulgare. This could have been due to spontaneous hybridization events between H. vulgare and H. spontaneum during expansion of cultivated barley.